This study is designed to characterize and define the cellular immune response to genital HSV infection, to describe the nature of this response, and to correlate the in vitro response to specific viral antigens as well as mitogens with the natural history, recurrence rate, clinical course, and severity of this infection. A cohort of patients with either primary or recurrent genital herpes simplex virus infection will be followed at regular intervals with physical examinations, sequential viral cultures, and studies of cell mediated and humoral immunity. Patients will undergo frequent, i.e., weekly studies with the lymphocyte transformation, lymphokine production in response to herpes antigen and standard mitogens to analyze fluctuations of the cellular immune response in relationship to recurrence and to the clinical severity of disease. In addition, studies to characterize the subpopulation of responsive and/or suppressor cells important in the cellular immune response to genital herpes virus infection will be performed. The relationship of these fluctuations in response to the recurrence rates and/or recrudescence patterns of disease will be characterized.